You know what happens when you take 5 multi-vitamins in one day right? Your body can not absorb all of those vitamins and so they leave our system without providing any benefit. Does this mean vitamins are bad? no. Does this mean vitamins are useless? no. It simply means that the human body can only absorb so much of any given substance in a single pass through the digestive system. More of a good thing is not always better.
This is true with chemical fertilizers that offer an all purpose 10-10-10 fertilizer. This means 10% nitrogen, 10% phosphates and 10% Potassium. Plants need nitrogen. Plants need phosphates. Plants need potassium. But plants can not absorb all that nitrogen and all those phosphates and all that potassium all at once. Most of that 10-10-10 will wash away into the water table. Too much chemical fertilizer and you will burn the roots. But even a common, all purpose 10-10-10 is like eating a whole bottle of vitamins and thinking that will be enough vitamins to last you the next 4 or 5 months. For the most part, chemical fertilizers just make your plants pee yellow. (See Nitrate Pollution)
Worm Castings are basically 0-0-0 yet they work better than a chemical 10-10-10. Why? How Could that be??
Rather than trying to feed your garden 2 or 4 or 6 months of food all at once, worm castings work to feed your plants in several ways. As worm castings break down very slowly they release nitrogen in a form best suited for plants to uptake through their roots.
The active microbes in worm castings help break down all the nutrients in the soil and convert them into forms easily available to the plant and it’s roots.
Worm castings also help hold water and oxygen in the soil. Exposure to water and oxygen not only feeds the plants directly but helps break down the other organic matter in the soil.
Worm Castings at 0-0-0 (or really 0.2-0.3-0.01) are really better for your plants than a commercial 10-10-10 or any general fertilizer regardless of their NPK values. The chemical fertilizer companies are the one’s who created the N-P-K scale to make it look like their products were better than nature. Sure if you don’t mind feeding your plants methane or natural gas based food…
Worm castings not only provide a slow release food source for your plants but worm castings will never burn your plants or over feed them. Worm castings work with the plants and the soil to feed plants everything they need at a rate they can absorb it… without peeing yellow.